By "which is an identity" they just mean "which trigonometric equation is true?"
What you have to do is take one of these and sort it out to an identity you know is true, or...
*FYI: You can always test identites like this:
Use the short angle of a 3-4-5 triangle, which would have these trig ratios:
sinx = 3/5 cscx = 5/3
cosx = 4/5 secx = 5/4
tanx = 4/3 cotx = 3/4
Then just plug them in and see if it works. If it doesn't, it can't be an identity!
Let's start with c, just because it seems obvious.
The Pythagorean identity states that sin²x + cos²x = 1, so this same statement with a minus is obviously not true.
Next would be d. csc²x + cot²x = 1 is not true because of a similar Pythagorean identity 1 + cot²x = csc²x. (if you need help remembering these identites, do yourslef a favor and search up the Magic Hexagon.)
Next is b. Here we have (cscx + cotx)² = 1. Let's take the square root of each side...cscx + cotx = 1. Now you should be able to see why this can't work as a Pythagorean Identity. There's always that test we can do for verification...5/3 + 3/4 ≠ 1, nor is (5/3 + 3/4)².
By process of elimination, a must be true. You can test w/ our example ratios:
sin²xsec²x+1 = tan²xcsc²x
(3/5)²(5/4)²+1 = (4/5)²(5/3)²
(9/25)(25/16)+1 = (16/25)(25/9)
(225/400)+1 = (400/225)
(9/16)+1 = (16/9)
(81/144)+1 = (256/144)
(81/144)+(144/144) = (256/144)
(256/144) = (256/144)
Answer:
43.
Step-by-step explanation:
Follow PEMDAS (Parentheses, exponents, multiply, divide, add, subtract). First you do 8-4 which is 4, then you multiply 4 by 4 which is 16 since you multiply next, then you add 27 to 16 which then gets you to 43.
Answer:
1000
Step-by-step explanation:
10milimeter=1 centimeter
100 centimeters=1 meter
10x100=1000
Let me know if im right :)
In a place value relationships. The relationship between 2
the same digit place next to each other is the value of the number to left is
10 times bigger than to the value to the left and from the decimal point to the
right is 10 times smaller of value than the digit in their right.<span>
</span>
Let say for example:<span>
1111
1 thousands, 1 hundreds, 1 tens, and 1 ones.
Let’s start from 1 = 1 x 10 = 10
That would be 10 X 10 = 100
then 100 X 10 = 1000
Notice that their value increase base on its place value if
we multiply the given number by 10. </span>
Another one is
912.98 in where 9 is hundreds, 1 is tens, 2 is ones and after
the decimal points, in where 9 is tenths and 8 is hundredths.<span>
<span>Notice each place value next to each other. Each value is ten
times in difference.</span></span>
